scispace - formally typeset
Search or ask a question
Author

Beryl Zaitlin

Bio: Beryl Zaitlin is an academic researcher from University of Calgary. The author has contributed to research in topics: Geosmin & Colorectal cancer. The author has an hindex of 12, co-authored 15 publications receiving 719 citations.
Topics: Geosmin, Colorectal cancer, Cancer, DNA repair, ERCC1

Papers
More filters
Journal ArticleDOI
TL;DR: Results indicate that a high fat diet in humans, associated with increased risk of colon cancer, may have its carcinogenic potential mediated through the action of bile acids, and that some dietary anti-oxidants may ameliorate this carcinogenicity.
Abstract: High dietary fat causes increased bile acid secretion into the gastrointestinal tract and is associated with colon cancer. Since the bile acid deoxycholic acid (DOC) is suggested to be important in colon cancer etiology, this study investigated whether DOC, at a high physiologic level, could be a colon carcinogen. Addition of 0.2% DOC for 8–10 months to the diet of 18 wild-type mice induced colonic tumors in 17 mice, including 10 with cancers. Addition of the antioxidant chlorogenic acid at 0.007% to the DOC-supplemented diet significantly reduced tumor formation. These results indicate that a high fat diet in humans, associated with increased risk of colon cancer, may have its carcinogenic potential mediated through the action of bile acids, and that some dietary anti-oxidants may ameliorate this carcinogenicity.

292 citations

Journal ArticleDOI
TL;DR: This paper attempts to elucidate the types and activities of actinomycetes that may be found in, or interact with, drinking water supplies.

191 citations

Journal ArticleDOI
TL;DR: Study of soils under barley and canola in northern Alberta indicates that differing practices within agricultural fields may not be the main determinant of actinomycete community size and diversity.

46 citations

Journal ArticleDOI
TL;DR: This research highlights the reasons for the lack of correlation between actinomycete isolations and taste and odor levels, and the need for further study on act inomycetes in relation to mussels.
Abstract: Actinomycete isolations were made from water, suspended sediment, periphyton, macrophytes, and mussels in the Lake Ontario system. Isolated actinomycetes were tested for production of the taste and odor compounds geosmin and 2-methyl-isoborneol. Actinomycetes found in this system were associated with suspended sediment, indicating a terrestrial origin, or were associated with mussels, indicating that some species may reside in association with mussel beds. Actinomycetes in the genus Streptomyces and actinomycetes in other genera both produced taste and odors, but not all isolates produced taste and odors, and those that did, did not do so under all conditions. This research highlights the reasons for the lack of correlation between actinomycete isolations and taste and odor levels, and the need for further study on actinomycetes in relation to mussels.

44 citations

Journal ArticleDOI
TL;DR: The substantial deficiencies in protein expression of DNA repair proteins Pms2, Ercc1 and Xpf in about 1 million crypts near cancers and TVAs suggests that the tumors arose in field defects that were deficient in DNA repair and that deficiencies in Pms 2, ErCC1 andXpf are early steps, often occurring together, in progression to colon cancer.
Abstract: Cancers often arise within an area of cells (e.g. an epithelial patch) that is predisposed to the development of cancer, i.e. a "field of cancerization" or "field defect." Sporadic colon cancer is characterized by an elevated mutation rate and genomic instability. If a field defect were deficient in DNA repair, DNA damages would tend to escape repair and give rise to carcinogenic mutations. To determine whether reduced expression of DNA repair proteins Pms2, Ercc1 and Xpf (pairing partner of Ercc1) are early steps in progression to colon cancer. Tissue biopsies were taken during colonoscopies of 77 patients at 4 different risk levels for colon cancer, including 19 patients who had never had colonic neoplasia (who served as controls). In addition, 158 tissue samples were taken from tissues near or within colon cancers removed by resection and 16 tissue samples were taken near tubulovillous adenomas (TVAs) removed by resection. 568 triplicate tissue sections (a total of 1,704 tissue sections) from these tissue samples were evaluated by immunohistochemistry for 4 DNA repair proteins. Substantially reduced protein expression of Pms2, Ercc1 and Xpf occurred in field defects of up to 10 cm longitudinally distant from colon cancers or TVAs and within colon cancers. Expression of another DNA repair protein, Ku86, was infrequently reduced in these areas. When Pms2, Ercc1 or Xpf were reduced in protein expression, then either one or both of the other two proteins most often had reduced protein expression as well. The mean inner colon circumferences, from 32 resections, of the ascending, transverse and descending/sigmoid areas were measured as 6.6 cm, 5.8 cm and 6.3 cm, respectively. When combined with other measurements in the literature, this indicates the approximate mean number of colonic crypts in humans is 10 million. The substantial deficiencies in protein expression of DNA repair proteins Pms2, Ercc1 and Xpf in about 1 million crypts near cancers and TVAs suggests that the tumors arose in field defects that were deficient in DNA repair and that deficiencies in Pms2, Ercc1 and Xpf are early steps, often occurring together, in progression to colon cancer.

42 citations


Cited by
More filters
Journal ArticleDOI
09 Apr 2015-Cell
TL;DR: It is demonstrated that Indigenous spore-forming bacteria from the mouse and human microbiota promote 5-HT biosynthesis from colonic enterochromaffin cells (ECs), which supply 5- HT to the mucosa, lumen, and circulating platelets and elevating luminal concentrations of particular microbial metabolites increases colonic and blood5-HT in germ-free mice.

2,047 citations

Journal ArticleDOI
02 Jan 2015-Science
TL;DR: It is shown that the lifetime risk of cancers of many different types is strongly correlated with the total number of divisions of the normal self-renewing cells maintaining that tissue’s homeostasis, suggesting that only a third of the variation in cancer risk among tissues is attributable to environmental factors or inherited predispositions.
Abstract: Some tissue types give rise to human cancers millions of times more often than other tissue types. Although this has been recognized for more than a century, it has never been explained. Here, we show that the lifetime risk of cancers of many different types is strongly correlated (0.81) with the total number of divisions of the normal self-renewing cells maintaining that tissue’s homeostasis. These results suggest that only a third of the variation in cancer risk among tissues is attributable to environmental factors or inherited predispositions. The majority is due to “bad luck,” that is, random mutations arising during DNA replication in normal, noncancerous stem cells. This is important not only for understanding the disease but also for designing strategies to limit the mortality it causes.

1,519 citations

Journal ArticleDOI
TL;DR: In this paper, the authors discuss links between the bacterial microbiota and cancer, with a particular focus on immune responses, dysbiosis, genotoxicity, metabolism and strategies to target the microbiome for cancer prevention.
Abstract: Microbiota and host form a complex 'super-organism' in which symbiotic relationships confer benefits to the host in many key aspects of life. However, defects in the regulatory circuits of the host that control bacterial sensing and homeostasis, or alterations of the microbiome, through environmental changes (infection, diet or lifestyle), may disturb this symbiotic relationship and promote disease. Increasing evidence indicates a key role for the bacterial microbiota in carcinogenesis. In this Opinion article, we discuss links between the bacterial microbiota and cancer, with a particular focus on immune responses, dysbiosis, genotoxicity, metabolism and strategies to target the microbiome for cancer prevention.

1,202 citations

Journal ArticleDOI
TL;DR: The mechanistic links between bile acids and gastrointestinal carcinogenesis in CRC and HCC are discussed, which involve two major bile acid-sensing receptors, farnesoid X receptor (FXR) and G protein-coupled bile Acid receptor 1 (TGR5).
Abstract: Emerging evidence points to a strong association between the gut microbiota and the risk, development and progression of gastrointestinal cancers such as colorectal cancer (CRC) and hepatocellular carcinoma (HCC). Bile acids, produced in the liver, are metabolized by enzymes derived from intestinal bacteria and are critically important for maintaining a healthy gut microbiota, balanced lipid and carbohydrate metabolism, insulin sensitivity and innate immunity. Given the complexity of bile acid signalling and the direct biochemical interactions between the gut microbiota and the host, a systems biology perspective is required to understand the liver-bile acid-microbiota axis and its role in gastrointestinal carcinogenesis to reverse the microbiota-mediated alterations in bile acid metabolism that occur in disease states. An examination of recent research progress in this area is urgently needed. In this Review, we discuss the mechanistic links between bile acids and gastrointestinal carcinogenesis in CRC and HCC, which involve two major bile acid-sensing receptors, farnesoid X receptor (FXR) and G protein-coupled bile acid receptor 1 (TGR5). We also highlight the strategies and cutting-edge technologies to target gut-microbiota-dependent alterations in bile acid metabolism in the context of cancer therapy.

905 citations

Journal ArticleDOI
TL;DR: The food changes performed in subjects from the same populations resulted in remarkable reciprocal changes in mucosal biomarkers of cancer risk and in aspects of the microbiota and metabolome known to affect cancer risk, best illustrated by increased saccharolytic fermentation and butyrogenesis and suppressed secondary bile acid synthesis in the African Americans.
Abstract: Rates of colon cancer are much higher in African Americans (65:100,000) than in rural South Africans (<5:100,000). The higher rates are associated with higher animal protein and fat, and lower fibre consumption, higher colonic secondary bile acids, lower colonic short-chain fatty acid quantities and higher mucosal proliferative biomarkers of cancer risk in otherwise healthy middle-aged volunteers. Here we investigate further the role of fat and fibre in this association. We performed 2-week food exchanges in subjects from the same populations, where African Americans were fed a high-fibre, low-fat African-style diet and rural Africans a high-fat, low-fibre western-style diet, under close supervision. In comparison with their usual diets, the food changes resulted in remarkable reciprocal changes in mucosal biomarkers of cancer risk and in aspects of the microbiota and metabolome known to affect cancer risk, best illustrated by increased saccharolytic fermentation and butyrogenesis, and suppressed secondary bile acid synthesis in the African Americans.

724 citations